Equations Flashcards
Sensitivity
= TP/ (TP+ FN)
Specificity
= TN / (TN + FP)
Positive predictive value
= TP / (TP + FP)
Negative predictive value
= TN / (FN + TN)
Odds ratio (for case control studies)
= (a/c) / (b/d) = ad / bc
Relative risk
= (a / (a+b)) / (c / (c+d))
Attributable risk
= (a / (a+b)) - (c / (c+d))
Relative risk reduction
= 1 - RR
Absolute risk reduction
= (c / (c+d)) - (a / (a+b))
Number needed to treat
= 1/absolute risk reduction
Number needed to harm
= 1/attributable risk
Hardy-Weinberg equilibrium
p^2 + 2pq + q^2 = 1
p + q = 1
Volume of distribution
= amount of drub in body / plasma drug concentration
Half-life
= (0.693 x Vd) / CL
Drug clearance
= rate of elimination of drug / plasma drug concentration = Vd x Ke (elimination constant)
Loading dose
= (Cp x Vd) / F
Maintenance dose
= (Cp x CL x r) / F
Cardiac output
= rate of O2 consumption/ (arterial O2 content - venous O2 content) = stroke volume x heart rate
Mean arterial pressure
= cardiac output x total peripheral resistance = 2/3 diastolic + 1/3 systolic
Stroke volume
= EDV - ESV
Ejection fraction
= SV / EDV = (EDV - ESV) / EDV
Resistance
= driving pressure / flow
Capillary fluid exchange
= net fluid flow = Kf((Pc-Pi) - s(nc-ni))
Renal clearance
= UxV / Px
